1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof.
2. Description of the Related Art
A so-called flat panel display (FPD) typified by a liquid crystal display device has characteristics of being thin and low power consumption. Therefore, flat panel displays are widely used in various fields. Among them, since an active matrix liquid crystal display device having a thin film transistor (TFT) in each pixel has high display performance, the market size is remarkably being expanded.
A plurality of scanning lines and signal lines is formed over an active matrix substrate used for an active matrix display device and these wirings intersect with each other with an insulating layer interposed therebetween. Thin film transistors are provided close to an intersection portion of the scanning line and the signal line and each pixel is switched (e.g., see Patent Document 1).